The present method and the apparatus, respectively, are applied in the production of anodes that are required for fused-salt electrolysis for the production of primary aluminum. These anodes are produced in a molding procedure as so-called “green anodes” or “raw anodes”, from petroleum coke, to which pitch is added as a binding agent, the anodes being sintered in an anode furnace subsequently to the molding procedure.
This sintering process is realized in a heat treatment process which takes place in a defined manner, and during which the anodes pass through three phases, namely a heating phase, a sintering phase and a cooling-down phase. In this case, the raw anodes are situated in a heating zone of a “fire” that is composed of the heating zone, a firing zone and a cooling zone and that is formed in the anode furnace, the raw anodes being pre-heated by the waste heat of already fully sintered anodes that originates from the firing zone, prior to the pre-heated anodes being heated to the sintering temperature of approximately 1200° C. in the firing zone. According to the state of the art as it is known, for example, from the document EP 1 785 685 A1, the different designated zones are defined by an alternately continuous arrangement of different modules above furnace chambers or heating ducts that receive the anodes.
The firing zone, which is arranged between the heating zone and the cooling zone, is defined by positioning a burner device or a so-called burner ramp above selected furnace chambers or heating ducts. Anodes that have been burned directly prior thereto, which means that have been heated to the sintering temperature, are situated in the cooling zone. Above the cooling zone, a blower device or a so-called cooling ramp is arranged, by means of which air is blown into the heating ducts of the cooling zone. By means of a suction device that is arranged above the heating zone or by means of a so-called suction ramp, the air is guided, via the heating ducts, from the cooling zone through the firing zone into the heating zone, and, from the latter, in the form of flue gas, guided through a flue gas cleaning system, being released into the surroundings. The suction device and the burner device form a furnace unit together with the cooling ramp and the heating ducts.
The above-described modules are displaced at regular time intervals along the heating ducts in the direction of the raw anodes that are arranged in the anode furnace. In this way, there can be provision for an anode furnace comprising several furnace units, the modules of which are displaced, subsequently to one another, above the furnace chambers or heating ducts for subsequent heat treatments of the raw anodes or anodes. In case of such anode furnaces, which can be embodied as open anode furnaces or annular anode furnaces in different designs, a number of further ramps, such as a measuring ramp, a pressure ramp as well as several additional cooling and burner ramps, is regularly used and functionally assembled in addition to the above-described modules or ramps. The individual different types of ramps have to be placed in a certain order and at a certain distance to one another so that they can be operated as one furnace unit in the desired manner. The ramps are displaced by operating personnel, manually or using a crane, at cyclical time intervals of, for example, 24 to 26 hours. For that purpose, operation of the furnace unit is interrupted and started again after the ramps have been re-positioned. In particular when the operating personnel shifts the ramps, it may happen that the ramps are faultily positioned relative to one another or that the different types of ramps are mounted in a faulty order. This can lead to procedural functional disorders and to dangerous operating statuses of the anode furnace with the risk of deflagrations, fires or explosions.
It is, for example, known to pass information on the respective positions of the ramps on through manual input into a control device of the furnace unit, for example a PLC installation. Thus, the ramp mounting is at least visually inspected. The operating personnel can, however, also make a mistake when readjusting the ramp position or when manually inputting said information. Therefore, it is still possible to start the furnace unit even though a ramp is mounted in a faulty position.